GNU Linux-libre 4.4.294-gnu1
[releases.git] / Documentation / ABI / testing / sysfs-block-dm
1 What:           /sys/block/dm-<num>/dm/name
2 Date:           January 2009
3 KernelVersion:  2.6.29
4 Contact:        dm-devel@redhat.com
5 Description:    Device-mapper device name.
6                 Read-only string containing mapped device name.
7 Users:          util-linux, device-mapper udev rules
8
9 What:           /sys/block/dm-<num>/dm/uuid
10 Date:           January 2009
11 KernelVersion:  2.6.29
12 Contact:        dm-devel@redhat.com
13 Description:    Device-mapper device UUID.
14                 Read-only string containing DM-UUID or empty string
15                 if DM-UUID is not set.
16 Users:          util-linux, device-mapper udev rules
17
18 What:           /sys/block/dm-<num>/dm/suspended
19 Date:           June 2009
20 KernelVersion:  2.6.31
21 Contact:        dm-devel@redhat.com
22 Description:    Device-mapper device suspend state.
23                 Contains the value 1 while the device is suspended.
24                 Otherwise it contains 0. Read-only attribute.
25 Users:          util-linux, device-mapper udev rules
26
27 What:           /sys/block/dm-<num>/dm/rq_based_seq_io_merge_deadline
28 Date:           March 2015
29 KernelVersion:  4.1
30 Contact:        dm-devel@redhat.com
31 Description:    Allow control over how long a request that is a
32                 reasonable merge candidate can be queued on the request
33                 queue.  The resolution of this deadline is in
34                 microseconds (ranging from 1 to 100000 usecs).
35                 Setting this attribute to 0 (the default) will disable
36                 request-based DM's merge heuristic and associated extra
37                 accounting.  This attribute is not applicable to
38                 bio-based DM devices so it will only ever report 0 for
39                 them.
40
41 What:           /sys/block/dm-<num>/dm/use_blk_mq
42 Date:           March 2015
43 KernelVersion:  4.1
44 Contact:        dm-devel@redhat.com
45 Description:    Request-based Device-mapper blk-mq I/O path mode.
46                 Contains the value 1 if the device is using blk-mq.
47                 Otherwise it contains 0. Read-only attribute.